1. Field of the Invention
The present invention relates to an angular velocity sensor, and more particularly, to an angular velocity sensor capable of improving sensitivity characteristics by controlling resonance frequencies in a driving mode and a sensing mode.
2. Description of the Related Art
Micro Electro-Mechanical Systems (MEMS) are a product of technology for manufacturing a specific portion of a system to have a delicate shape in a μm unit by using a silicon process, which means an apparatus in which mechanical parts, sensors, actuators, or electronic circuits are integrated on a single silicon substrate.
A representative application for the MEMS technology is a sensor. In particular, among sensors, MEMS are frequently used for an angular velocity sensor to measure angular velocity.
In this case, the angular velocity sensor has been widely used for various industrial applications such as home appliances, vehicles, robots, military equipment, or the like, to determine the motion, posture, and position of an object. With the development of MEMS technology, the angular velocity sensor has become inexpensive and small, such that its applications have been significantly expanded.
Sensitivity of the angular velocity sensor depends on a resonance frequency. However, the resonance frequency shows a tendency to move out of a designed value due to manufacturing distribution, environmental change, and time lapse of the angular velocity sensor.
Due to these phenomena, the sensitivity characteristics of the angular velocity sensor may be degraded. Therefore, a need exists for a method of correcting a resonance frequency so as to improve the sensitivity characteristics thereof.
The related art has improved the sensitivity of the angular velocity sensor by changing the resonance frequency according to electrostatic force generated by applying a DC bias voltage. However, the related art requires high voltage and increases power consumption, which results in limitations in the applications thereof to small-sized mobile devices.
Therefore, research into an angular velocity sensor having improved sensitivity characteristics by correcting errors of the resonance frequency according to the manufacturing distribution or the environment when mass produced, without requiring additional power consumption or the application of high voltage, is urgently needed.